例如,timestamp1 - timestamp2将返回两个时间戳之间的时间间隔。 下面是一个示例查询,演示如何计算两个日期之间的小时差异: 代码语言:txt 复制 SELECT EXTRACT(HOUR FROM timestamp1 - timestamp2) AS hour_diff FROM your_table; 在上面的查询中,timestamp1和timestamp2是要比较的两个时间戳,your_table是包含...
test=# select extract (hour from timestamp '2017-07-31 22:18:00'); date_part 22 (1 row) 12. min (得到时间中的分钟) test=# select extract (min from timestamp '2017-07-31 22:18:00'); date_part 18 (1 row) 13. sec (返回时间中的秒) test=# select extract (sec from timestam...
extract(field from timestamp) double 获取子域 extract(hour from timestamp '2001-02-16 20:38:40') 20 extract(field from interval) double 获取子域 extract(month from interval '2 years 3 months') 3 localtime time 今日的时间 localtimestamp timestamp 日期和时间 now() timestamp 当前的日期和...
test=# select extract (doy from timestamp '2017-07-31 22:18:00'); date_part --- 212 (1 row) 11. hour (小时) test=# select extract (hour from timestamp '2017-07-31 22:18:00'); date_part --- 22 (1 row) 12. min (得到时间中的分钟) test=# select extract (min from time...
EXTRACT函数 用于取出时间中的一部分,比如取出小时部分,参数示例如下: 综合示例 获取当前据本周五23:59还有多少小时多少分钟 select EXTRACT(HOUR FROM(CURRENT_DATE + time '23:59') - CURRENT_TIMESTAMP) + (6 - extract(dow from current_date) )*24 "hour", ...
PostgreSQL 时间/日期函数和操作符 日期/时间操作符 下表演示了基本算术操作符的行为(+,*, 等): 操作符例子结果 + date '2001-09-28' + integer '7'date '2001-10-05' + date '2001-09-28' + interval '1 hour'timestamp &#..
-- 增加1小时 SELECT timestamp + interval '1 hour' AS new_timestamp FROM table_name; -- 减少1天 SELECT timestamp - interval '1 day' AS new_timestamp FROM table_name; 复制代码 获取当前时间戳: SELECT NOW(); 复制代码 获取时间戳的年、月、日等部分: SELECT EXTRACT(YEAR FROM timestamp...
date_trunc('hour', interval '2 days 3 hours 40 minutes')→ 2 days 03:00:00 extract ( field from timestamp ) → double precision 获取时间戳子字段 extract(hour from timestamp '2001-02-16 20:38:40')→ 20 extract ( field from interval ) → double precision 获取时间间隔子字段 extract(...
make_time(hour int, min int, sec double precision) 函数通过指定小时、分钟和秒数创建一个时间。 SELECT make_time(1, 2, 30.5); make_time| ---| 01:02:30.5| make_timestamp(year int, month int, day int, hour int, min int, sec double precision) 函数通过指定年、月、日、时、分、...
EXTRACT() function The PostgreSQL EXTRACT() function is used to retrieves subfields such as year or hour from date/time values. The source must be a value expression of type timestamp, time, or interval. The field is an identifier or string that selects what field to be extracted from th...